As a hinge device of this type, there are a hinge device for an auto car with which a door is used to open and closes an opening of a vehicle body while maintaining the parallel attitude of the door relative to the vehicle body and a hinge device with which a door is used to open and close an opening of a body while maintaining the parallel attitude of the door relative to the body of an airplane (see patent document 1).
As illustrated in FIG. 15, a link 73 is connected to a vehicle body 71 of an auto car and its door 72. An end of the link 73 is connected to an axis part 71a of the vehicle body 71 rotatably and the other end of the link 73 is connected to an axis part 72a of the door 72 rotatably. Besides, a first pulley 74 is connected integrally with the axis part 71a of the vehicle body 71 and a second pulley 75 is connected integrally with the axis part 72a of the door 72. Between these first pulley 74 and second pulley 75, a timing belt 76 is placed thereover.
When the door 72 gets opened or closed, the link 73 rotates on the axis part 71a of the vehicle body 71 and the door 72 turns on the axis part 71a of the vehicle body 71. Here, the link 73 rotates a predetermined angle in the clockwise direction around the axis part 71a of the vehicle body 71, the first pulley 74 fixed to the axis part 71a of the vehicle body 71 is rotated a predetermined angle in the counterclockwise direction relative to the link 73. Counterclockwise rotation of the first pulley 74 relative to the link 73 is transmitted to the second pulley 75 by the timing belt 76, and the second pulley 75 rotates a predetermined angle in the counterclockwise direction relative to the link 73. The attitude of the door 72 relative to the vehicle body 71 is defined by combination of the rotation angle of the link 73 relative to the axis part 71a of the vehicle body 71 and the rotation angle of the second pulley 75 relative to the link 73. As the rotation angle of the link 73 and the rotation angle of the second pulley 75 relative to the link 73 cancel out each other, when opening or closing the door 72, the attitude of the door 72 is maintained fixed and the door 72 is pivoted around the axis part 71a of the vehicle body 71 while it keeps parallel with the back-and-forth direction of the vehicle body 71.
In such a hinge device, the axis part 71a of the vehicle body 71 is fixed to the inner surface of the vehicle body 71 and the axis part 72a of the door 72 is fixed to a back surface of the door 72. Therefore, if the open angle of the door 72 is to be increased, the link 73 interferes with the inner surface of the vehicle body and the open angle of the door 72 cannot be increased. In order to increase the open angle of the door 72, as illustrated in FIG. 16, the link 73 and the timing belt 76 are bent into L shape at their midpoint so as to prevent interference of the link 73 and the timing belt 76 with the inner surface of the vehicle body 71.